“When Do I Need to Refill My Forklift Battery’s Water?”

There are two main types of batteries: Those that can be recharged and those that cannot. Electric forklifts usually have lead-acid batteries, although some newer models have lithium-ion batteries, which are considered alkaline rechargeable batteries.

Among lead-acid batteries — by far the most common type for forklifts — there are two different types: valve-regulated (also known as “maintenance free” batteries), and vented batteries.

Closed vs Open Systems

Valve regulated batteries have a closed system, so the hydrogen and oxygen produced during the charging process does not escape through evaporation and instead is absorbed back into the battery’s water. As a result, you can’t add water to these types of batteries. In other words, they don’t need to be topped off.

With vented batteries, however, the hydrogen and oxygen produced during the charging process is evaporated into the atmosphere. Consequently, they require regular topping off with fresh water.

Protecting Yourself from Hazards

When topping off batteries with water, personal protective gear such as safety glasses and gloves are recommended. You also should empty your pockets of any metal objects that could fall into the battery or bridge across terminals.

Work in an area that has no potential ignition sources,such as open flames, sparks or other electrical equipment. Don’t use a mobile phone when working near batteries. If you are using tools to remove caps or covers, use only single-ended tools with insulated handles.

Using a Water Level Log

Water levels on your forklift battery should be checked weekly. A good plan is to designate a particular date and time and assign the responsibility of checking the water level to one employee. A log should be kept of when the water level was checked, who checked it, and what was the reading.

This log should be regularly reviewed by managers to ensure there are no dramatic changes in the frequency of the watering as this can indicate a problem with the battery.

Water levels also can be check every time you charge your battery. Sometimes the water in the battery will appear to be boiling during charging. This is actually just the release of hydrogen and oxygen resulting from the hydrolysis in a process known as “gassing”.

Most forklift batteries have a maximum and minimum fill line. The water level should well above the minimum fill line. If it falls below this line, there won’t be enough electrolyte in the battery — the combination of water and sulfuric acid used to conduct electricity between the transport of ions between the positive and negative plates within the battery’s cells. Put plainly, your battery won’t work properly.

Dangers of Overfilling

Don’t fill the water level above the maximum fill line because overfilling the battery can cause the acid to come into contact with metal surfaces like the battery case or the lift truck components. This can seriously damage the vehicle.

In some cases, sulfuric acid can be added to the water. Click here to learn if you need to do this for your battery.

If you accidentally overflow the battery, the entire battery needs to removed from the forklift and rinsed with water. The lift truck compartment also needs to be cleaned. Make sure to wear personal protective gear to protect yourself from acid burns.